Golf training apparatus and method

ABSTRACT

Techniques for training and correcting a golf swing are described. A golfer places a ball at a teeing point on a teeing surface which is tiltably adjustable about a horizontal tilt axis. A catch device is aligned with a target direction passing through the teeing point and extending perpendicularly to the tilt axis. The golfer aims along the target direction and executes a golf swing to strike the ball from the teeing point. The actual direction of travel of the struck ball is determined. An azimuth difference is determined between the target direction and the actual direction of travel of the struck ball. The tilt angle of the teeing surface is varied about the tilt axis based upon the azimuth difference between the target direction and the actual direction of travel of the struck ball.

This invention relates to a golf training apparatus and method, andparticularly but not exclusively concerns a means for indicating whethera golf practice shot has been hooked, or sliced.

It is known from U.S. Pat. No. 4,432,552 to provide legs which areadjustable in height to support the elevated table at different anglesrelative to the horizontal. This adjustment is intended to allowdifferent terrains to be simulated (e.g. a downhill lie of the ball, anuphill lie of the ball, and side slopes to the left or right).

It is also known from U.S. Pat. No. 4,432,552 (Saverino) to provide golfpractice apparatus consisting of an elevated table or platform having anartificial grass surface and supported on a plurality of legs, each ofwhich is adjustable in height and a golf club of reduced length for usein combination with the table. This shortened club allows full swingpractices to be made within the confines of a normal room, and theraised table enables the golfer to hit a ball with the short club whilemaintaining a correct stance. However, although such an apparatus allowsa golfer to execute a full golf swing, the apparatus does not provide anindication as to whether the swing is being performed correctly, in thatno means is provided for determining a horizontal azimuth direction ofthe golf ball when the ball is struck.

It is an object of the present invention to provide a golf trainingapparatus which allows the golfer to determine the horizontal azimuthdirection of the golf ball and thus correct his swing to eliminatehooked shots or sliced shots from the majority of the golfer's shots,thus allowing the golfer to practice so that the number of shots struckstraight increases.

It is an object of the present invention to provide a golf trainingmethod and apparatus which allows a golfer to correct his swing byaltering the angle his spine makes relative to the horizontal at themoment of impact with the ball by adjusting the angle of a playingsurface of a teeing apparatus.

According to a first aspect of the present invention, there is provideda golf training apparatus comprising:

-   -   an adjustable playing surface defining a starting position for a        golf ball; and    -   a direction indicating means for indicating a horizontal azimuth        direction of a ball struck from a starting position, comprising:    -   means to define a vertical plane through which the ball is        intended to pass, and    -   means for determining a horizontal position of an intersection        of a path taken by said ball with said vertical plane.

A second aspect provides a golf swing training method, wherein theazimuth direction of a struck ball is determined, and correction is madeto elements of the golfer's swing on the basis of the determineddirection. The elements may be to the golfer's stance or grip, or to hisposition relative to the ball prior to striking.

An advantage for a golfer using such a golf training apparatus andmethod 15 that he can determine the initial horizontal direction of thegolf ball after it has been struck, thereby allowing him to correct hisswing.

Embodiments of the invention will now be described by way of example andwith reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram showing the elements in a golf trainingapparatus;

FIG. 2 is a plan view showing possible paths that a golf ball might takebetween a tee and a ball position detecting means;

FIG. 3 is a schematic diagram showing a teeing apparatus in perspectiveview;

FIG. 4 is a schematic diagram showing the teeing apparatus with adifferent angle of tilt;

FIGS. 5A to 5E are schematic diagrams showing how the teeing apparatusmay be used to correct a golfer's swing;

FIG. 6A is a schematic diagram showing a catch net in a furtherembodiment;

FIG. 6B is a schematic diagram showing a catch net in yet anotherembodiment;

FIG. 7 is a schematic diagram showing a golf training apparatus in afurther embodiment.

FIG. 1 shows an apparatus for improving a golfer's golf swing in a firstembodiment. The apparatus is designed so that it may be used indoors andcomprises a number of elements, namely a teeing apparatus 1, a shortenedgolf club 11, a practice golf ball 13 (which is lighter than a standardgolf ball) and catch net 17. The raised teeing apparatus 1 is providedwith a flat teeing surface 5 supported by supporting legs 3 which attheir ends are provided with means 9 for adjusting the angle of tilt ofthe raised teeing apparatus 1 (these will be described later in relationto FIG. 4). The teeing surface 5 of the raised teeing apparatus 1 ispreferably provided with an artificial turf strip 7 which emulates theplaying surface on a golf course. The golf club 11 is a standard golfclub head with a shortened shaft. The provision of the shortened golfclub 11 and the raised teeing apparatus 1 allows the use of the trainingapparatus indoors because the shortened golf club 11 allows the golfer15 to practice using a full swing without risk of hitting a ceiling. Theshortened golf club 11 in combination with the lighter than standardgolf ball 13 also contribute to the reduction of the ball's energy whena shot is taken in comparison with a golf shot hit outdoors. This isbecause the golf club 11 imparts less initial impulse to the golf ball13 and because the golf ball 13 is lighter, the momentum of the golfball 13 is lower than that of a standard golf ball.

The catch net 17 is provided with a number of adjacent verticallyextending openings 19 through one of which the ball 13 may pass when thegolfer 15 plays a shot. Spaces behind each of said openings 19 are eachenclosed by retaining means 20 for halting the progress of the ball 13after it has passed through opening 19. The openings 19 are eachprovided at their respective lower end with a respective collectingpouch 21. Thus when a shot is played, the golf ball may pass through oneof the openings 19 and is retained by the associated retaining means 20which is formed of a netting material and this material stops the balland subsequently the ball drops into the pouch 21 provided at the lowerend of the opening 19.

The catch net 17 is suspended from support 23 which in this particularembodiment is a stand comprising an upright 23 a, a pair of suspensionarms 23 b and a base 23 c.

For use, the teeing apparatus 1 is placed approximately 1.5 metres fromthe catch net, with the teeing surface 5 aligned so that the ball 13 maybe struck towards the catch net. The golfer's objective is to hit theball through a particular one of the openings 19 of the catch net 17.Preferably, a central opening 19 of an array of adjacent openings isselected as the objective.

After the golfer 15 has taken his shot he can determine whether the ballwas hit to the left, to the right or straight by observing the pouch 21in which the ball 13 has come to rest. If the pouch 21 of the opening 19aimed at contains the ball, then the shot was straight. If the pouch 21of another opening 19 contains the ball, then the direction of the shotcan be determined as being left or right, depending on the position ofthe pouch 21 containing the ball relative to the opening 19 aimed at.The deviation from the aiming point indicates the angle (i.e. thedeviation of the club face from a direction perpendicular to the golfer)of the golf club head upon impact with the golf ball 13, thus allowingthe golfer 15 to correct any defects in his swing action so thatsubsequent shots can be hit straight. Thus by using the apparatus thegolfer 15 may be trained so that his golf swing improves.

The plan view of the golf training apparatus as shown in FIG. 2illustrates in more detail the components provided on the playingsurface 5 and also possible directions that the golf ball 13 may travelwhen struck (these horizontal vectors are illustrated by dashed lines 24and 25 for shots hit to the left and right and a solid line 26 for ashot which is hit straight). The artificial turf strip 7 is providedwith markings 27 which indicate points at which the ball may be placedwhen taking a shot. The teeing surface 5 is also provided withindicators 28 which allow the golfer to assess his entry swing (thesewill be explained in more detail in relation to FIG. 3). The playingsurface 5 may also be provided with instructions 29 to remind the golfer15 of certain steps to be taken before taking a shot (e.g. instructionsto remind the golfer to check whether his grip, aim, stance and postureare correct before taking a shot).

FIG. 3 shows in greater detail the raised teeing apparatus 1. Theindicators 28 for indicating the line of entry swing are provided inrecesses in the playing surface 5 and are hinged (not shown) at one endso that they may stand upright. When the golfer takes a swing, if hisswing is correct then the indicator 28 will remain upright, conversely,if the golfer's entry swing is incorrect then the club will impact withthe indicator 28 and move it to its down position. In this particularembodiment, two of these indicators 28 are provided, positionedsymmetrically about a centre line of the playing surface 5 so that theraised tee 1 can be used by both left-handed and right-handed golfers.

In this figure, it can be seen that the adjusters 9 which allow theheight/playing angle of the raised tee to be altered are rotatably fixedto the legs 3 of the raised teeing apparatus 1. These adjusters 9 areeccentrically mounted thus allowing a variety of differentheights/angles of tilt to be achieved. These adjusters 9 are provided onthe raised teeing apparatus 1, and allow the lateral as well as thelongitudinal inclination of the apparatus to be altered so that a golfer15 may train other aspects of his golf swing. In an alternativeembodiment, adjusters may be provided only at one end of the raised tee,to provide longitudinal angular adjustment only. As an alternative tothe eccentric adjusters, the teeing apparatus may be provided withadjustable telescopic legs.

If, when the playing surface is horizontal, a golfer's body position atthe point of impact between the golf club 11 and golf ball 13 is suchthat he leans away from the direction of the shot (as seen in FIG. 4),hooking will result. To train the golfer out of this leaning habit, theadjusters 9 are used to tilt the teeing surface 5.

FIG. 5A represents schematically a golfer using the shortened club 11and the teeing apparatus 3. As can be seen from this figure, at thepoint of impact between golf club 11 and golf ball 13, the golfer isleaning away from the direction of the shot (the same as in FIG. 4). Asa result of this defect in his swing, the majority of shots taken by thegolfer will be hook shots. FIG. 5B shows how the swing of the golfer inFIG. 5A can be corrected. The adjusters (not shown) of the teeingapparatus 3 are used to tilt the playing surface 5 so that it slopesdownwards in the direction of the swing. This urges the golfer to alterhis stance so as to position his spine perpendicular to the playingsurface 5 at the point of impact between golf club 11 and golf ball 13thus placing him in an upright position at this instant. By practisingshots adopting this upright position, the golfer will become trained totake shots in an upright position. Thus when the teeing apparatus 3 isremoved, the golfer continues to adopt the correct position at themoment of impact as shown in FIG. 5C.

FIG. 5D schematically represents a golfer who habitually leans in thesame direction as the shot at the point of impact between golf club 11and golf ball 13, thus causing the majority of shots taken to be sliced.As can be seen in FIG. 5E the adjusters (not shown) on the teeingapparatus 3 can be adjusted in this case to incline the playing surfaceso as to slope upwards in the direction of the swing. The golfer isurged to adjust his swing so as to adopt an upright position at theinstant of impact, by bringing his spine perpendicular to the playingsurface 5. By practising shots with the teeing apparatus 3 inclined inthis way, the golfer's swing can be corrected as described previously sothat when the teeing apparatus 3 is removed the golfer adopts a correctposition at the point of impact between golf club 11 and golf ball 13,as shown in FIG. 5C. Both of these methods of tilting the playingsurface 5 so that the golfer has to alter his swing when playing a shotallow the golfer to train his swing so that the number of shots hit tothe left or right may be reduced and the number of straight shots may beincreased.

FIG. 6A illustrates the catch net 17 in another embodiment. The positiondetecting means 17 is essentially the same as that in the previousembodiment except that the retaining means 20 of the central opening 19and pouch 21 have been removed. This apparatus may be used inconjunction with a full size golf club and standard weight ball on agolf driving range, for instance. The golfer aims the shot to passthrough a central opening 19A. Shots hit to the left or right will thenbe caught by the retaining means 20 and straight shots are allowed topass through the opening 19A.

FIG. 6B shows an asymmetric catch net 17 in a further embodiment. Thecatch net 17 is essentially the same as that in the first embodimentexcept that openings 19 and pouches 21 on one side of the verticalcentre line of the catch net 17 have been removed and are replaced withplain netting. In the example shown, this would be used to correct agolfer's swing where the majority of shots are hit to the right. Theposition of the openings 19 to the left of the centre line of the balldetecting means 17 forces the golfer to play shots to the left. Trainingusing the catch net of this embodiment will allow the golfer to correcthis swing. Another feature which is different from that of the firstembodiment is the provision of the additional pouches 22 at the oppositeend of the opening 19 from the pouches 21. This then allows the catchnet 17 to be rotated by 180° in its plane about a point X so that theopenings 19 are on the right of the centre line. Thus training may beundertaken to correct a swing where the majority of shots are hit to theleft. In an alternative, the slots may have pouches at one end only andthe catch net rotated by 180° about axis AB and retaining means 20turned “inside out” to provide an oppositely-handed asymmetric catchnet.

The above advantage can also be achieved by using the catch net 17 ofthe first embodiment. This can be done by simply positioning the net 17so that the central opening 19 of the net 17 does not correspond withthe centre line of the raised teeing apparatus 1, and the net 17 thus isoffset to either the left or right of the centre line of the raisedteeing apparatus 1.

FIG. 7 shows a golf training apparatus in a further embodiment wherelike reference numerals are used for those features of the apparatuswhich are the same as in previous embodiments. In this embodiment, asimple net 43 is used to stop the golf ball 13. The direction that thegolf ball takes after it has been struck is determined by using a lineof LEDs 35 arranged at one end of the teeing apparatus 5 perpendicularlyto the intended line of travel of the ball. Each LED emits a light beam.As the golf ball 13 passes through said light it will reflect (due tothe ball's reflective surface) light beams back to a line of photodiodes37 each one of which corresponds to one of the LEDs 35. A photodiode 33is also provided on the artificial turf strip 7 and it is on thisphotodiode 33 that the ball 13 is placed prior to a shot being taken.When the golf ball 13 is struck the photodiode 33 is uncovered and thissignals to a control unit such as a PC 41 to start measuring the outputsof each of the photodiodes 37. The output voltage V_(n) (where n=diodenumber) of each of the photodiodes 37 is measured at discrete timeintervals T₁ to T_(n). The PC 41 then checks the profile of the diodeoutput over time for each diode by calculating V_(n)T_(n)−V_(n)T_(n−1)for each diode. When the ball is struck it will pass over one of theplurality of LEDs 35 and thereby reflect the light beam back onto thecorresponding photodiode 37. For the purposes of illustration the diodeover which the ball passes shall be given the reference M.V_(m)T_(n)−V_(m)T_(n−1) will be greater than zero for this diode. If adiode n is not the diode over which the ball has passed, then thecomputer will check the output of the next diode n+1 and then calculateV_(n+1)T_(n)−V_(n+1)T_(n−1) to check whether or not the signal isgreater than zero. The PC 41 continues this process until the diode mwhere V_(m)T_(n)−V_(m)T_(n−1) is greater than zero is found. Thedirection of the ball is thus determined, since the starting point isknown and the point where the ball crosses the line of diodes is known.The computer may then display either a qualitative or a quantitativeindication, either telling the golfer “Left”, “Right” or “Straight”, andoptionally indicating the degree of deviation from a straight shot. Thedisplay may optionally also give instructions to the golfer to alterthe, angle of the playing surface of the teeing apparatus 5.

In a further aspect, the adjustable teeing apparatus of the presentinvention can be used to assist a golfer in determining the correct lieangle for selecting his golf clubs.

The “lie angle” of a set of golf clubs is the acute angle which the clubshaft makes with the plane of the sole of the club head, i.e. the anglebetween the club shaft and the ground when the golfer is addressing theball. In such a position, the sole of the club should be 1 to 2 mm aboveground level, at the toe end of the club (i.e. the end remote from thehandle).

Golf clubs are manufactured in a number of different lie angles, so thatclubs with standard shaft lengths can be used by golfers of differentheights. Conventionally, clubs are manufactured with a “standard” lieangle and with lie angles of one and two degrees greater than or lessthan the “standard” angle. The “standard” angle is approximately 120 to125 degrees. Shorter golfers will require clubs having a smaller lieangle, so that when the ball is addressed, the handle is not positionedtoo far from the ground for the golfer to grip satisfactorily. A tallergolfer will require clubs with a larger lie angle, so that when the clubhead is correctly positioned relative to the ball, the handle of theshaft is higher above the ground.

To determine the correct lie angle for a particular golfer, a shortenedclub having a known shaft length and lie angle is given to the golfer,who is then asked to address a ball placed on the teeing surface at apredetermined height. By inspecting whether the sole of the club headlies parallel to the teeing surface and at the correct spacing, it canbe ascertained whether the lie angle of the club is correct.

If the heel of the club head (that part of the club head nearest to theshaft connection or hosel) is spaced further from the teeing surfacethan the toe of the club head (that part of the club head furthest fromthe shaft connection or hosel), then the teeing surface can be raised sothat the angle of the club changes to make the sole of the club parallelto the teeing surface. Conversely, if the heel of the club head iscloser to the teeing surface than the toe of the club head, then theteeing surface can be lowered to make the sole of the club parallel tothe teeing surface.

By providing a shortened golf club of a known length, when the shortenedgolf club is used by a golfer to address a ball and is positionedcorrectly relative to the teeing surface, the height of the teeingsurface above the ground can give an indication of the correct lie anglefor a full-sized club for this golfer.

According to this aspect, a method of determining the correct lie anglefor golf clubs for a golfer comprises providing the golfer with a shortgolf club of known length, addressing a ball placed on a teeing surface,adjusting the height of the teeing surface until the head of the shortgolf club is correctly positioned relative to the teeing surface, andnoting the height of the teeing surface above ground level. The correctlie angle for full-sized golf clubs for the golfer can then bedetermined by referring to a table correlating the height of the teeingsurface above the ground with the correct lie angle. Alternatively, theheight-adjusting mechanism of the teeing surface may be provided withgraduated indicia relating either to the height of the teeing surfaceabove ground level, or directly to the required lie angle for full-sizedclubs.

An apparatus for use in the method for determining the correct lie anglefor golf clubs for a golfer comprises a short golf club of apredetermined length, a height-adjustable teeing surface, means todetermine the height of the teeing surface above ground level, and meansto correlate the height of the teeing surface above ground level withthe correct lie angle for full-sized clubs (clubs of a known, longer,shaft length) for the golfer.

An apparatus for use in the method for determining the correct lie anglefor golf clubs for a golfer comprises a short golf club of apredetermined length, a height-adjustable teeing surface, means fordetermining the height of the teeing surface above ground level, andmeans to correlate the height of the teeing surface above ground levelwith the correct lie angle for full-sized clubs (clubs of a known,longer, shaft length) for the golfer.

In a further refinement of this aspect, the height of the teeing surfacewhen the golfer addresses a ball with the shortened golf club can beused to determine not only the lie angle required for use with golf clubshafts of a standard length, but can be used to provide a correlationbetween the required lie angle and the length of the shaft which thegolfer wishes to use for his clubs. By measuring the height of theteeing surface when the golfer correctly addresses a ball using theshortened club of known length, an indication of the height above groundlevel of the golfer's hands is obtained. The golfer can then select thelength of shaft he wishes to use, and a simple geometrical calculationwill provide the correct lie angle. Alternatively, the golfer can selecthis required lie angle and a calculation can provide the correct shaftlength for that golfer, based on the height above ground level of thegolfer's hands when addressing the ball.

In a preferred arrangement, a table can be compiled wherein each valuefor the height of the teeing surface above the ground is associated witha plurality of shaft lengths and with a like number of lie angles, eachlie angle being associated with a particular shaft length. When thecorrect height of the teeing surface has been ascertained, the golfercan simply consult the table to determine a desired combination of shaftlength and lie angle to suit his requirements.

1. A method for training and correcting a golf swing, comprising:placing a ball at a teeing point on a teeing surface which is tiltablyadjustable about a horizontal tilt axis; aligning a catch device with atarget direction passing through the teeing point and extendingperpendicularly to the tilt axis; aiming along the target direction andexecuting a golf swing to strike the ball from the teeing point;determining an actual direction of travel of the struck ball;determining an azimuth difference between the target direction and theactual direction of travel of the struck ball; and varying the tiltangle of the teeing surface about the tilt axis based upon the azimuthdifference between the target direction and the actual direction oftravel of the struck ball.
 2. The method of claim 1, wherein the step ofdetermining the actual flight direction of travel of the struck ballcomprises catching the ball in a compartment in the catch device.
 3. Themethod of claim 2, wherein the catch device comprises a plurality ofcompartments arranged in a horizontal row, and wherein each compartmentcorresponds to a respective actual direction of travel of the ball fromthe teeing point to the catch device.
 4. The method of claim 3, whereinthe step of determining the actual flight direction of travel of thestruck ball comprises catching the ball in a compartment in the catchdevice, and determining on which side of the target direction thecompartment lies.
 5. The method of claim 1, wherein the step of varyingthe tilt angle of the teeing surface about the tilt axis based upon theazimuth difference between the target direction and the actual directionof travel of the struck ball comprises tilting the teeing surfacetowards the catch device when it is determined that the actual directionof travel of the struck ball is on a side of the target directiontowards the golfer.
 6. The method of claim 1, wherein the step ofvarying the tilt angle of the teeing surface about the tilt axis basedupon the azimuth difference between the target direction and the actualdirection of travel of the struck ball comprises tilting the teeingsurface away from the catch device when it is determined that the actualdirection of travel of the struck ball is on a side of the targetdirection away from the golfer.